Conventional flexible hoses have been manufactured for many years, first out of natural rubber and more recently out of petrochemical derivatives such as synthetic rubber, thermoplastic rubbers, or polymers. Conventional flexible hoses commonly have a layered construction consisting of an inner tubular conduit, a spiraled, braided, or knitted reinforcement wrapped about the tubular conduit, and an outer cover.
“Kinking” is a phenomenon that may occur when the hose is doubled over or twisted. A consequence of kinking is that the fluid flow through the hose can be either severely restricted or blocked. Kinking is a nuisance that causes the user to waste time unkinking the hose. Extreme kinking may occur when, for example, a newly purchased coiled garden hose is initially used. At the time of initial use, a coupling at one end of the hose is fastened to a faucet. The user typically grasps the opposite end of the hose and move away from the faucet without allowing the coiled hose to untwist. Kinking also occurs after the initial use as a consequence of routine movements by the user.
When a hose kinks, water flow through the hose is blocked. The user must then attempt to remove the blockage by manual manipulation, such as by swinging the hose to relax the kink or approaching the kinked location and manually straightening the kink. Certain kinks may require the user to return to the faucet, shut off the flow at the faucet to release the fluid pressure in the hose, and then manually unkink the hose. The user suffers further inconvenience because he or she must walk back, reestablish the flow of water through the hose, and then return to the opposite end of the hose to continue use. An even more acute problem arises when the user has already attached a large sprinkler device, such as an oscillating sprinkler to the end, and is forced to untwist the hose with this device attached.
The tendency of flexible hoses to kink may be at least partially alleviated by winding a helical wrap about the exterior of the inner tubular conduit. However, because of the choice of construction materials for the wrap and conduit, such kink resistant hoses achieve enhanced flexibility by sacrificing crush resistance to an externally applied force. When these reinforced hoses are deformed, for example by walking on or driving over them with a car, the helical wrap tends to permanently deform. The permanent deformation restricts the fluid path. Another approach for increasing the kink resistance of flexible hoses is to increase the wall thickness of the tubular conduit. However, increasing the wall thickness sacrifices hose flexibility such that these hoses are more cumbersome for a user to handle and manipulate. Increasing the wall thickness also makes the hose heavier.
Thus, an improved hose construction is desired that is characterized by a suitable physical property combination of kink resistance, crush resistance, and burst resistance.